ES2906337T3 - Resonant-vibratory mixing - Google Patents

Abstract

Apparatus (10) to generate agitation comprising: a base (37); a first movable mass (12), wherein said first movable mass is movable in a first linear direction and in an opposite linear direction; a second movable mass (11), wherein said second movable mass is movable in the same directions as said first movable mass and is movably connected to said first movable mass by a first resilient means (25) and is movably connected movable to said base (37) by means of a second elastic means (27); a linear electromagnetic force transducer (38) rigidly connected to the first moving mass (12) and operative to produce a first vertical force on the first moving mass (12) in the first linear direction and a second vertical force on the first mass (12) moving in the opposite linear direction; and a third movable mass (13), wherein said third movable mass (13) is movable in the same directions as said first movable mass (12) and is movably connected to said second movable mass (11) by a third elastic means (26), in which the third mobile mass (13) is not directly connected to the first mobile mass (12).

Description

DESCRIPTION

Resonant-vibratory mixing

Background of the invention

The present invention generally relates to the mixing and conveying of masses. In particular, the invention relates to an apparatus and method for resonant-vibratory mixing.

Fluid mixing involves the creation of fluid motion or agitation that results in the uniform distribution of initial heterogeneous or homogeneous materials to form an output product. Mixing procedures are necessary to achieve uniform distribution of: miscible fluids, such as alcohol in water; immiscible fluids such as oil-in-water emulsification; of particulate material such as the suspension of pigment particles in a carrier fluid; mixtures of dry materials with fluids such as sand, cement and water; thixotropic (pseudoplastic) fluids with solid particles; chemical ingredients of pharmaceutical products; and biological samples, such as bacteria, while growing in a culture medium without incurring physical damage.

The mixing can be done in various ways: one or more rotating impellers mounted on one or more shafts immersed in the fluid mixture stir the fluid and/or the solid materials to be mixed, or a perforated plate with displacement movement performs the stirring, or the container containing the materials itself is shaken, shaken or vibrated. Mixing can be continuous (such as using a rotating impeller or vibrating the holding vessel) or intermittent, such as when the drive mechanism turns on and off in one or more directions.

With a conventional vibratory mixer, the amplitude can be varied within very narrow limits, and the frequency is generally set at the frequency of the alternating current (AC) power supply. Even when using a frequency controlled motor drive, the vibration frequency of a conventional vibratory mixer can be varied only within relatively narrow limits. Mixing at the mechanism's natural resonant frequency is generally avoided due to the high loads and associated wear on the mechanisms.

When biological tissue is cultured, all cells must be suspended in the nutrient broth; that is, the cells should not settle to the bottom of the container in which they are being grown. However, when shaking live cells in order to minimize sedimentation, the mechanical effect of the high shear caused by the shaker should not compromise the integrity of the cells. In the case of rotary shakers, quite frequently, the culture medium creates a turbulent vortex into which the cells are sucked. Under turbulent vortex conditions, cells are at increased risk of mechanical damage and continuous oxygen supply to cells is not consistently ensured.

The prior art is characterized by US Patent Nos. 2,091,414, 3,162,910, 2,353,492, 2,636,719, 3,498,384, 3,583,246, 3,767,168, 4,619,532, 4,972,930, 5,979,242 , 6,213,630, 6,250,792, 6,263,750 and 6,579,002. Newport et al. in US Patent No. 2,091,414 describe an apparatus for applying vibrations. This invention is limited in that it only describes a single mass system.

Behnke et al. in US Patent No. 3,162,910 describe an apparatus for shaking foundry flasks. This invention is limited in that only a single mass, single spring assembly system is provided. The present invention overcomes the limitations of US Patent Nos. 2,353,492 and 2,636,719 issued to John C. O'Connor (the "O'Conner patents") and 6,213,630 issued to Olga Kossman (the "O'Conner patent"). Kossmann"). The O'Conner patents describe devices that allow vibratory compaction of dry materials and the feeding of material by means of vibratory conveying. The Kossman patent claims electronic control of motors for vibration control of a compaction device.

The O'Conner patents describe vibratory mechanisms composed of two masses. A means for applying a cyclic force is attached to the first mass. The second mass, containing or including the material to be affected, is elastically mounted to the first mass. The assembly is then supported by elastic members in a fixed position on the ground. This mechanism can be effectively adjusted by appropriate elastic member selections to substantially reduce the forces transmitted to the ground position, but is limited in its ability to reduce the accelerations imposed on the first mass. Accelerations on the first mass, including the induction of cyclic forces by the drive, induce high forces which, in turn, lead to premature failure. To reduce drive failure rates, induced forces must be reduced or the mass of affected material must be severely limited. Both cases limit the applications available on the device. In addition, it is stated that the operating conditions preferred are between the first and second modes of maximum vibrations. This further limits the effectiveness of the device due to the additional energy required to operate in this range to achieve optimum mixing amplitudes and accelerations. If the device is to be operated in one of the peak modes, only enough power would be required to overcome the inherent damping of the device to achieve maximum acceleration and amplitude at mass two.

The Kossman patent describes a method of controlling the motor(s) of a vibratory device similar to the O'Conner patent. The disclosed device lacks the ability to operate at natural frequency peaks and also lacks the ability to limit the forces transmitted to the drive or ground positions.

Ogura, in US Patent No. 3,498,384, describes a vibratory impact device. This invention is limited in that only a two-mass system is described. It is not possible to achieve high payload accelerations, force cancellation and low drive accelerations with a two-mass system.

Stahle et al. in US Patent No. 3,583,246 describe a vibration device driven by at least one imbalance generator. This invention is limited in that it only describes a single mass system.

Dupre et al., in US Patent No. 3,767,168 describe a mechanical stirring apparatus. This invention is limited in that it only describes a single mass system.

Schmidt, in US Patent No. 4,619,532, describes an agitator for paint containers. This invention is limited in that it only describes a dual mass system.

Davis, in US Patent No. 4,972,930, describes a dynamically adjustable, rotary unbalance agitator. This invention is limited in that it only describes a single mass system. Furthermore, the vibratory drive is fixed directly to the single mass and this mass is fixed to the ground by means of pneumatic springs. High drive accelerations are an unavoidable result of such a device.

Hobbs, in US Patent No. 5,979,242, describes a multi-level vibration test system with controllable vibration attributes. This invention is limited in that it describes a multi-drive system with a drive attached to each of the masses in the system. No description is provided of means for achieving low drive accelerations or low ground transmission forces.

Krush et al., in US Patent No. 6,250,792, describe an integrated vibratory adapter device. This invention is limited in that it only describes a single mass system.

Maurer et al. in US Patent No. 6,263,750 describes a device for generating directed vibrations. This invention is limited in that it only describes a single mass system.

Bartick et al., in US Patent No. 6,579,002 describes a high performance, fast oscillating, wide range, high load capacity programmable laboratory shaker. This invention is limited in that it only describes a single mass system. This invention is not capable of operating in a resonant state as it is driven by displacement rather than vibration.

In summary, the prior art does not describe a three-mass system having a structure that is capable of achieving low frequencies of 0-1,000 Hertz (Hz), high accelerations of 2-75 times the acceleration due to gravity (g), and large displacement amplitudes of 0.254-12.7 mm (0.01-0.5 in). What is needed is an apparatus and method for mixing fluids and/or solids in a manner that can be varied from a manner in which the integrity of the fragile biological and molecular materials in the mixing vessel is maintained to a manner in which the one that homogenizes the heavy aggregate material by supplying large amounts of energy.

EP 0393492 A2 describes the prior art.

Brief summary of the invention

The scope of the invention is set forth in the appended claims.

The purpose of the invention is to provide thorough and deep processing, eg mixing of a plurality of fluids, eg thorough mixing of a gas into a liquid, or a liquid into another liquid, or more than two phases . One application is the mixing and dispersion of solids in liquids, particularly hard to wet solids and small particles. Other applications include the preparation of emulsions for chemical and pharmaceutical applications, the gasification of liquids for purification and for chemical reactions, the acceleration of physical and chemical reactions, and the suspension of fine particles in fluids. The fluids to which referenced herein may or may not include entrapped solid particles.

The present invention provides an apparatus and method for mixing materials, which apparatus and method provide exquisite control over mixing in a wide range of applications. Applications range from heavy-duty or heavy-duty agitation for concrete preparation to the delicate and precise mixing required for the preparation of pharmaceuticals and the processing of biological cultures in which living organisms must remain viable throughout the process. of the mixing procedure. In a preferred embodiment, the present invention provides a vibratory mixer, driven by electronically controllable motor(s), adapted to allow virtually unlimited control of the mixing process.

An example not forming part of the present invention is made up of three masses, with a cyclic linear force applied to one of the masses. Linear force applied to the first mass produces a vibratory motion that is transmitted through resilient members to a second mating mass and then to a third mass. With the addition of a second mass, it is possible to adjust the response of the system so that the transmitted forces cancel out. A container is attached to the second or third masses for the purpose of mixing two or more constituents. The three masses are coupled together with elastic members that are optimized to transfer the vast majority of the force to the mixing bowl and to minimize the force transmitted to the ground and support structure. Minimizing the transmission of force to the ground and maximizing the force transmitted to the container more efficiently affects the work done on the contents of the container and reduces wear on the linear force transducer. More efficient operation is achieved by operating at or near the resonant frequencies of the mechanism. Employing the resonant system described herein, intensity levels are easily achieved that are nearly impossible with conventional vibratory mixing methods.

An object of the preferred embodiments of the invention is to facilitate the mixing of two or more liquids. Another object of the preferred embodiments of the invention is to facilitate the mixing of one or more liquids and one or more gases. Still another object of the preferred embodiments of the invention is to facilitate the mixing of one or more liquids and one or more gases. Another object of the preferred embodiments of the invention is to facilitate the mixing of one or more liquids with one or more solid particles. A further object of the preferred embodiments of the invention is to facilitate the mixing of one or more liquids with one or more solid particles with one or more gases. Still another object of the preferred embodiments of the invention is to facilitate the mixing of two or more solids. Another object of the preferred embodiments of the invention is to facilitate the mixing of two or more non-Newtonian materials. A further object of the preferred embodiments of the invention is to facilitate the mixing of one or more non-Newtonian materials with one or more solid particles.

Another object of the preferred embodiments of the invention is to facilitate the gasification of liquids. Still another object of the preferred embodiments of the invention is to facilitate the degassing of liquids. Another object of the preferred embodiments of the invention is to speed up physical and chemical reactions. A further object of the preferred embodiments of the invention is to accelerate heat transfer. Another object of the preferred embodiments of the invention is to speed up mass transfer. Still another object of the preferred embodiments of the invention is to suspend and distribute particles. A further object of preferred embodiments of the invention is to suspend nanoparticles and distribute particles. Another object of the preferred embodiments of the invention is to cause micromixing. Another object of the preferred embodiments of the invention is to create Newtonian instabilities. Still another object of the preferred embodiments of the invention is to cause high gas-liquid and liquid-gas mass transfer rates. Another object of the preferred embodiments of the invention is to cause vapor bubbles to disperse at the surface and to disperse in the liquid. A further object of preferred embodiments of the invention is to cause bubbles to move downward into a liquid. Another object of the preferred embodiments of the invention is to cause bubbles to be suspended in a liquid. Another object of the preferred embodiments of the invention is to cause vapor to cavitate in a liquid.

Still another object of the preferred embodiments of the invention is to facilitate mixing by a selected frequency, amplitude, or acceleration. Another object of the preferred embodiments of the invention is to disperse fine particles in a uniform manner in a liquid Newtonian or non-Newtonian medium. A further object of preferred embodiments of the invention is to cause liquids to migrate into porous solids. Another object of preferred embodiments of the invention is to cause liquids to migrate through porous solids. Another object of the preferred embodiments of the invention is to cause liquids to migrate into porous solids and leach from the materials. Still another object of the preferred embodiments of the invention is to reduce boundary layers that impede mass transport and heat transfer. Another object of the preferred embodiments of the invention is to employ a resonant operation to improve mixing efficiency. A further object of the preferred embodiments of the invention is to combine three or more masses in a manner that provides a force canceling mode of operation. Another object of the preferred embodiments of the invention is to produce low frequencies of 0-1,000 Hertz (Hz), high accelerations of 2-75 times the acceleration caused by gravity (g) and large displacement amplitudes of 0.254-12.7 mm (0.01-0.5 in). Still another object of the preferred embodiments of the invention is to provide a self-contained system for placing fluids and solids to be mixed on a platform and a mechanism for securing the system to the platform. Another object of the preferred embodiments of the invention is to provide a means for forcing cancellation of the base of the device.

Another object of the preferred embodiments of the invention is to reduce acceleration in the oscillator, thereby increasing bearing life and prolonging the life of device components. Still another object of the preferred embodiments of the invention is to provide mechanisms for resonant frequency operation of the device for greater efficiency and effectiveness. Another object of the preferred embodiment of the invention is to employ cancellation of internal forces and reduce forces transmitted to the environment of the device. A further object of the invention is to efficiently transfer the applied forces and related accelerations to the payload mass and reduce the acceleration of the oscillator. Another object of the preferred embodiments of the invention is to allow automatic and/or manual adjustment of the oscillatory force during operation. Another object of the preferred embodiments of the invention is to provide a three or more mass system, in which the operating parameters (frequency and displacement) are less sensitive to changes in payload mass and which provides consistent operation in a diversity of situations.

Another object of the preferred embodiments of the invention is a device that has three vibration modes and operates at maximum capacity, thus allowing the use of more compatible springs, which reduces intrinsic damping and increases efficiency. Still another object of the preferred embodiments of the invention is to provide high mass transport of gases, liquids and nutrients to cells with low shear. Another object of the invention is to provide high mass transport of gases and waste products from cells with low shear. A further object of preferred embodiments of the invention is to provide high mass transport of gases, liquids and nutrients to and from microcarriers with low shear while causing a minimum of microcarrier collisions. Another object of preferred embodiments of the invention is to provide high mass transport of gases to and from microcarriers with low shear stress while causing a minimum of microcarrier collisions.

Still another object of the preferred embodiments of the invention is to provide a vibratory device that can be adjusted to produce frequencies and displacements that cause the fluids (gas-liquid, gas-liquid-solid systems and combinations of these systems) in the payload develop a resonant/mixed state that establishes high levels of gas-liquid contact, a standing acoustic wave, and axial flow patterns that result in high levels of gas-liquid mass transport and mixing. Another object of the preferred embodiments of the invention is to provide a vibratory device that can be adjusted to move a payload, such as a container filled with a variety of solids that are highly loaded, for example very close to theoretical density, through a frequency and amplitude that cause the material to fluidize and mix deeply. A further object of the invention is to provide a vibratory device that can be adjusted to displace a payload, such as a container filled with various solids and liquids that are highly loaded, for example very close to theoretical density, at a frequency and an amplitude that cause the material to fluidize and mix deeply. Another object of the preferred embodiments of the invention is to provide a vibratory device composed of two or more masses, a substantially linear vibrator and a control procedure, which allows the cancellation of variable forces during operation, in which the masses are connected by resilient members for the purpose of transferring the forces generated by the vibrator to the container and wherein the force cancellation is controllable such that substantially linear forces can be generated in any direction.

Additional aspects of the invention will become apparent from a consideration of the drawings and the description below of the preferred embodiments of the invention.

Brief Description of the Various Views of the Drawings

Features of the invention will be better understood with reference to the accompanying drawings, which illustrate presently preferred embodiments of the invention. In the drawings:

Fig. 1 is a front elevational view of the flat plate resonant reactor constructed according to a first example not forming part of the invention with some elements omitted for the sake of clarity.

Fig. 2 is a right side sectional view of the flat plate resonant reactor of Fig. 1.

Fig. 3 is a perspective view of the example of Figs. 1 and 2 with some elements omitted for clarity.

Fig. 4 is a front elevational view of the example of Figs. 1-4 with some elements omitted for the sake of clarity.

Fig. 5 is a diagram showing the transmission force response behavior of the example of Figs. 1-4.

Fig. 6 is a diagram showing the phase response behavior of the example of Figs. 1-4. Fig. 7 is a perspective view of a three-mass system according to the invention with a side-mounted vibration unit.

Fig. 8 is a perspective view of a three-mass system according to the invention with a low-mounted vibration device.

Fig. 9 is a side or front view (they are the same) of a mass system according to the invention with a centrally mounted vibration unit.

Fig. 10 is a graph showing performance differences between a two-mass system and a preferred embodiment of a three-mass system.

Fig. 11 is a schematic free body diagram of a preferred embodiment of the invention.

Fig. 12 is a perspective view of a second preferred embodiment of the invention.

Fig. 13 is a perspective view of the resonant system of the second preferred embodiment of the invention. Fig. 14 is a perspective view of the base assembly of the second preferred embodiment of the invention. Fig. 15 is a perspective view of a reaction mass assembly of the second preferred embodiment of the invention.

Fig. 16 is a perspective view of the drive assembly of the second preferred embodiment of the invention.

Fig. 17 is a perspective view of the payload assembly of the second preferred embodiment of the invention. Fig. 18 is a perspective view of the engine block assembly of the second preferred embodiment of the invention.

Fig. 19 is a perspective view of an engine assembly of the second preferred embodiment of the invention. In the drawings, the following reference numerals are used to indicate the parts and environment of the invention:

10 device, apparatus

11 intermediate mass

12 oscillator mass

13 payload, payload mass

24 payload mass springs to ground

25 oscillator springs to intermediate mass

26 springs from payload mass to intermediate mass

27 intermediate mass springs to ground

30 stops

37 floor frame, base, rigid structure

38 oscillator drives, servo motors, force transducers

39 payload-to-ground mass alignment struts

40 retainers

lock nuts

oscillator to intermediate mass alignment struts intermediate mass to ground alignment struts payload mass to intermediate mass struts eccentric masses, eccentric weights, eccentrics driveshafts, axles

mixing chamber

resonant system

base set

payload set

controller set

reaction mass set

base legs

leg connector assemblies

lower spring support

top spring bracket

base leg

sections

uprights

trim weight

base connector

reaction mass springs to base

reaction mass springs to payload cylinder block assembly

shaft drive supports

drive spring shafts

top spring flange

loaded drive springs

vertical payload mounts

top payload plate

payload bottom plate

base payload docks

drive spring shaft holes motor assemblies

engine mounts

144 heat sink

146 power connector

148 feedback connector

150 access holes

160 motor stator housing

162 self-aligning bearing

164 wave springs

166 motor stator

168 motor rotor

170 motor shaft

172 keys

176 counterweight spreader

178 angular contact ball bearing

180 rotor resolve

182 motor weight casing

184 stator resolve

190 snap ring

Detailed description of the invention

With reference to Figs. 1-4, an example is presented that does not form part of the present invention. The device 10 comprises three independent moving masses (intermediate mass 11, oscillator mass 12 and payload 13) and four different spring beds or spring systems (payload mass springs 24 to ground, oscillator mass springs 25 to ground). intermediate mass, intermediate mass springs 26 to payload and intermediate mass springs 27 to ground) that are housed in rigid structure 7. The oscillator ground 12 is preferably located between the other two ground. The intermediate ground 11 is preferably located below the oscillator ground 12. The payload 13 is preferably located above the oscillator mass 12. Preferably, all the masses are constructed of steel or some comparable alloy.

Oscillator ground 12 is rigidly connected to two oscillator drives 38 (eg, two direct current (DC) servo motors) and is movably connected to intermediate ground 11 via oscillator alignment struts 43 . to intermediate ground (wherein preferably two of them are rigidly connected to oscillator ground 12), oscillator to intermediate ground springs 25 (comprising four compatible springs), two retainers 40 and two lock nuts 41. The intermediate mass 11 is movably connected to the rigid structure 37 by means of intermediate mass alignment struts 53 to the ground (in which preferably four of them are rigidly connected to the rigid structure 37), mass springs 27 intermediate to floor (comprising eight compatible springs), four retainers 40 and four locking nuts 41. The payload 13 is movably connected to the intermediate mass 11 by means of payload mass to intermediate mass struts 55 (wherein preferably two of them are rigidly connected to the payload mass 13), springs 26 from payload mass to intermediate mass (comprising four compatible springs), two retainers 41 and two lock nuts 40. One end of the payload mass to intermediate mass springs 26 abuts against stops 30 which are preferably rigidly connected to the payload mass to intermediate mass struts 55 . The payload 13 is also movably connected to the rigid structure 37 by means of ground payload mass alignment struts 39 (preferably four of which are rigidly connected to the payload 13), springs 24 payload mass to ground (comprising eight compatible springs), four retainers 40 and four lock nuts 41.

Fig. 2 is a right side view of the example presented in Fig. 1 showing additional details. It is evident that the intermediate mass 11 supports the payload mass 13 and the oscillator mass 12 in parallel. Furthermore, the oscillator ground 12 is not directly connected to the payload ground 13. In this figure, a cover part of one of the servo motors 38 is not shown, so that one of the motor shafts 57 and one of the 56 eccentric masses are visible.

In another example, the device 10 further comprises a mixing chamber 60. Preferably, the mixing chamber 60 is fixed to the intermediate mass 11 or the payload 13. The dough that does not have the mixing chamber 60 attached to it may also be divided into multiple doughs, each with its own elastic member attachment means for attaching the dough to the dough that does not have the mixing chamber 60 attached to it. the same.

With reference to Figs. 3 and 4, the example of Figs. 1 and 2 is illustrated with elements removed from the corner of the device 10 that is closest to the viewer in Fig. 3. In these views, both oscillator units 38 are visible.

In yet another example, additional servo motors 38 may be added to device 10 to allow for variability in driving force while device 10 is in operation. With the addition of two more servo motors 38 with identical eccentric masses 56, a total cancellation of the forces can be achieved. This is achieved by setting all the motor shafts to be parallel to each other, with two motors rotating clockwise and two motors rotating counterclockwise. Preferably, the eccentric masses 56 are selected so as to cancel all forces at startup by setting the phase angle to 180 degrees for pairs of counter-rotating motors. When the motors have reached the desired frequency of rotation, the eccentric masses 56 are moved out of phase, thus creating a driving force. Phase angle movement is achieved by decelerating two of the motors for a fraction of a revolution and then resetting the selected rotational frequency so that the eccentric masses no longer oppose each other. The deceleration of the motors is performed by a servomotor motion control unit.

The operation of the example illustrated in Figs. 1-4 is achieved by the synchronized rotation by the servomotors 8 of eccentric weights 56 of equal mass and inertial properties that are fixed to each end of the axes 57 of the servomotors 38. The synchronization of the rotation of the two axes 57 is performed by electronic controls. The rotary axes 57 of the two servomotors 38 are oriented parallel to each other and are operated in opposite directions of rotation with their eccentric weights 56 opposite each other on the horizontal axis and coincident on the vertical axis. This arrangement produces substantially vertical linear forces with cancellation of the horizontal forces.

The centerline axis of each of the shafts 57 and the centroid of the attached eccentric masses 56 form a mass plane. Over the course of one revolution, the home position has the ground planes parallel to each other with the eccentric masses 56 on each axis above the motor plane defined by the two parallel motor shafts 57 . Within a quarter of a turn, the ground planes coincide with the motor plane and the eccentric weights 56 on each of the shafts 57 are closer together. The centrifugal forces created by the eccentric masses 56 are translated into the motor plane. This force has the same magnitude, but opposite direction, for each of the axes 57. This effectively cancels the force in the plane of the motor. In a half revolution, the mass planes are again perpendicular to the drive plane and the eccentric masses 56 are all below the drive plane. The centrifugal force acting on each of the shafts 57 is in the same direction, perpendicular to the motor plane. At three-fourths of a revolution, the mass planes and motor plane coincide again, but the eccentric masses 56 on each of the shafts 57 are oriented away from each other. Here, once again, the centrifugal forces created by the eccentric masses 56 are translated into the motor plane. Once again, this force is of the same magnitude, but opposite direction, for each of the axes 57. This effectively cancels the force in the plane of the motor. In one complete revolution, the mass planes are again perpendicular to the drive plane and the eccentric masses 56 are all above the drive plane. The centrifugal force acting on each of the axes has the same direction, perpendicular to the motor plane. The force acting perpendicular to the plane of the motor is translated vertically through the connecting springs to the intermediate mass 11. A further translation is then achieved via linear guides and the springs from the intermediate mass 11 to the payload mass 13. The springs comprising spring beds 24, 25, 26 and 27 are selected to optimize the transmission of force through the intermediate mass 11 to the payload mass 13 and to minimize the transmission to the supporting structure 37 and the environment. surrounding.

Resonant operation is determined when the disparity between the vibration level of the payload mass and the vibration level of the drive mass is maximized. This resonant state depends on the selected spring/mass system. Preferably, the spring characteristics and mass weights are chosen such that the resonant state can be achieved for the anticipated payload weight.

Operation in the resonant state is not always necessary to achieve the desired level of mixing. Operation near resonance provides substantial amplitude and accelerations to produce significant mixing. Desired mixing levels are established by matching time requirements with dispersion requirements. To mix faster or more vigorously, the amplitude is increased by operating closer to resonance. Operation is typically within 10 Hz of resonance. As the frequency approaches the resonant state, small changes produce large results (the slope of the frequency curve versus amplitude changes rapidly as the resonant state is approached).

The mixing container 60 (in which the materials for mixing are placed) is preferably attached to the mass 3 of payload. Vigorous mixing is achieved when the transmitted force is converted into an acceleration and displacement amplitude that push the components of the mixture up and down, producing a toroidal flow with secondary eddies.

In a further example, two additional servomotors 38 are added to the mechanism shown in Figs. 1-4. The two additional servomotors 38 are equipped with eccentric weights 56 that have the same physical characteristics as those indicated above. With these additional motors 38, a control of the driving force is possible. This is accomplished by controlling the relative phase angle between the two sets of motors 38. In a manner similar to that described above, the two sets of servo motors 38 are electrically controlled to achieve full cancellation of forces at all frequencies. Once the desired frequency is achieved, the relative phase angle between the two sets of motors is changed until the desired driving force is achieved. This arrangement has the added advantage of producing variable force and frequency. In another example, the variable elastic members are replaced by springs 24, 25, 26 and/or 27 to allow for changes in resonant frequency. This addition also allows for greater payload variability without sacrificing performance. The variable elastic members can be mechanically or electronically controlled. Examples of such devices are air-filled bellows, variable-length leaf springs, coil spring wedges, bimetallic piezoelectric springs, or any other member that can be used as an elastic member that also has the ability to have its spring rate change. or if it is not affected.

Instead of mixing by inducing bulk fluid flow, as is the case for impeller agitation, ResonantSonic® agitation produced by the present invention performs mixing by inducing microscale turbulence by propagating acoustic waves through medium. It is different from ultrasonic agitation in that the frequency of acoustic energy is lower and the mixing scale is larger. Another distinctive difference from ultrasonic technology is that ResonantSonic® devices are simple, mechanically driven shakers that can be made large enough to perform industrial-scale tasks at a reasonable cost.

One difference between the acoustic agitation technology described herein and conventional impeller agitation is the scale at which complete mixing occurs. In impeller agitation, mixing occurs by creating large-scale eddies that are reduced to smaller-scale eddies when energy is dissipated by viscous forces. With acoustic agitation, mixing occurs by acoustic transmission, which is the time-independent flow of fluid induced by a sound field. It is caused by the conservation of momentum dissipated by the absorption and propagation of sound in the fluid. Acoustic transmission transports "microscale" eddies through the fluid, estimated to be on the order of 100-200 µm. Although the eddies are microscale, the entire reactor mixes well in an extremely short time because acoustic transmission causes the microscale vortices to be transmitted uniformly throughout the fluid. The device 10 in Figs. 1-4 is preferably operated at resonance to produce strong displacement and acceleration to provide vigorous mixing potential. Fig. 5 shows an aspect of the response of the example presented in Figs. 1-4 to operation at various oscillator frequencies. The graph shows the force transmitted to the ground by the device 10 when it is operated at each indicated frequency. Operation at the first harmonic frequency of device 10 (point A) and at the second harmonic frequency of device 10 (point B) are indicated by the force peaks shown on the graph. During operation, a user selects an operating frequency at or near the third mode (ie, at or near the third harmonic frequency of device 10 or point C) as appropriate for the level of mixing desired.

Fig. 6 shows another aspect of the response of the example presented in Figs. 1-4 for operation at various oscillator frequencies. The phase of movement of the payload mass 13 and the reaction mass (eg, the intermediate mass 11) is illustrated. Above a frequency of about 40 Hertz (Hz), the phase difference between the payload mass 13 and the reaction mass is about 180 degrees, indicating that they are moving in opposite directions.

Figs. 7, 8 and 9 are embodiments of the present invention that are alternatives to the three-mass system of Figs. 1-4, but differ from those examples in the type of force transducers 38 used. These figures depict a device 10 that is driven by linear electromagnetic force transducers 38 as opposed to the examples of Figs. 1-4. All other functions of device 10 are equivalent to the preferred embodiment described above.

Referring to Fig. 7, a single linear electromagnetic force transducer 38 is rigidly attached to one side of the oscillator mass 12. Oscillator ground 12 is movably connected to ground 11 intermediate by means of oscillator springs 25 to intermediate mass. The payload mass 13 is movably connected to the intermediate mass 11 by means of payload-to-intermediate-mass springs 26 . The intermediate mass 11 is movably connected to the base 37 by means of intermediate mass springs 27 to the ground. Referring to Fig. 8, oscillator mass 12 and payload mass 13 are located at approximately the same elevation and both are above intermediate mass 12. This illustrates that the relative locations of the masses may vary between embodiments.

Referring to Fig. 9, a single linear electromagnetic force transducer 38 is rigidly attached to one half of the oscillator mass 12. The oscillator mass 12 is movably connected to the intermediate mass 11 by means of intermediate mass oscillator springs 25 . The payload mass 13 is movably connected to the intermediate mass 11 by means of payload-to-intermediate-mass springs 26 . The intermediate mass 11 is movably connected to the base 37 by means of intermediate mass springs 27 to the ground.

Referring to Fig. 10, accelerations produced by three-mass systems of the type described herein are compared to accelerations produced by two-mass systems described in the prior art. Points on line F represent oscillator mass accelerations produced by associated force inputs and points on line G represent payload mass accelerations produced by associated force inputs in a two-mass system . Points on line H represent oscillator mass accelerations produced by associated force inputs and points on line I represent payload mass accelerations produced by associated force inputs in a three-mass system .

Referring to Fig. 11, a free body diagram of the preferred embodiment of the invention of Figs. 1-4. The following are the equations of motion for device 10:

m1a1 = - k1X1 - cw1 k2(x2 - X1) k3(x3 - X1) c2(v2 - v1) c3(v3 - v1)

m2a2 = - k2(x2 - X1) - c2(v2 - v1) F

m3a3 = - k3(X3 - X1) - c3(v3 -v1) - k4X3 - c4v3

where

mx = mass x

kx = index of elasticity of the spring x

cx = damping coefficient of shock absorber x

xx = position of mass x

vx = velocity of mass x

ax = acceleration of mass x

F = applied force

By solving these equations simultaneously, the appropriate mass weights and spring rates and damping coefficients for the springs can be selected for the preferred embodiments of the invention. A person of ordinary skill in the art would be able to write similar equations for other embodiments of the invention.

There are an infinite number of solutions to the above three equations of motion that describe the motion of the three-mass system of device 10. Optimization of the system depends on the desired operation of the system. In general, the selection of spring mass and sizes is subject to maximizing payload amplitude, minimizing forces transmitted to the ground, and minimizing actuation amplitude. A preferred embodiment uses the spring rates as follows; ki/ki = 1, k2/k1 = 4.6, lo/k1 = 3.9, IWki 1.3, and mass ratios of; m1/m1 = 1, m2/m1 = 1.17, m3/m1 = 0.6. The damping constants are the result of natural damping in the preferred embodiment and are not real components. Therefore, the values of the damping constants are preferably determined by tests after the manufacture of an embodiment. With reference to Figs. 12-19, another preferred embodiment of device 10 is presented. As shown in Fig. 12, resonant system 70 is essentially enclosed by base assembly 72 in this embodiment.

Referring to Fig. 13, base assembly 72 is removed from device 10 to show only one embodiment. preferred system 70 resonant. In this embodiment, resonant assembly 70 comprises payload assembly 74, drive assembly 76, and reaction mass assembly 78.

Referring to Fig. 14, resonant system 70 is removed from device 10 to show only one preferred embodiment of base assembly 70. Base assembly 70 comprises four base legs 80 with each adjacent pair of base legs 80 connected by two leg connector assemblies 82 . A lower spring support 84 and an upper spring support 86 are attached to each of the base legs 80 . Preferably, a base leg 88 is attached to the bottom of each of the base legs 80.

Referring to Fig. 15, a preferred embodiment of the reaction mass assembly 78 is presented. In a preferred embodiment, four sets of reaction mass are included in the resonant system 70. In this embodiment, the reaction mass assembly 78 comprises two legs 100 that are connected by struts 102. In a preferred embodiment, an adjustment weight 104 is attached to each of the struts 102. Base connectors 106 support each of the two reaction masses to the base springs 108. In a preferred embodiment, the base reaction mass springs 108 are Part No. RHL 200-400 from Moeller Manufacturing Company of Plymouth, Michigan. Reaction mass to payload springs 110 movably connect reaction mass assembly 78 to payload assembly 74 . In a preferred embodiment, the reaction mass to payload springs 110 are Part No. RHL 250-450 from Moeller Manufacturing Company of Plymouth, Michigan.

In a preferred embodiment, a three-mass system is adjusted to minimize forces transmitted to the ground. This is achieved by selecting a reaction mass (mass m3) such that the ground forces cancel. From Fig. 6, it is evident that the mass m1 (payload mass) and the mass m3 (reaction mass) are 180 degrees out of phase (moving in opposite directions). If the weights of the masses are the same, or slightly modified by the natural damping constants, the forces will cancel so that zero net force is transferred to the ground.

Referring to Fig. 16, a preferred embodiment of drive assembly 76 is presented. In this embodiment, the drive assembly 76 comprises a powerhead assembly 120 to which two shaft drive mounts 122 are attached. Two drive spring pins 124 are attached to the ends of each of the pin supports 122 . An upper spring flange 126 is attached to the top of each of the drive spring shafts 124 . In a preferred embodiment, eight drive-to-payload springs 128 are attached to each end of each of the drive-to-shaft mounts 122 and to each upper spring flange. Drive-to-payload springs 128 movably connect drive assembly 76 to payload assembly 74 . In a preferred embodiment, the drive-to-payload springs 128 are Part No. RHL 125-450 from Moeller Manufacturing Company of Plymouth, Michigan.

Referring to Fig. 17, a preferred embodiment of the payload assembly 74 is presented. In this embodiment, the drive assembly 76 comprises eight vertical payload mounts 130 to which an upper payload plate 132 and a lower payload plate 134 are attached. Both the upper payload plate 132 and the lower payload plate 134 have four drive spring shaft holes 138 through which the drive spring shafts 124 pass when the device 10 is assembled. Preferably, eight springs. Payload-to-base springs 136 are attached to the upper payload plate 132 and eight payload-to-base springs 136 are attached to the lower payload plate 134. Payload-to-base springs 136 movably connect payload assembly 74 to base assembly 72 . In a preferred embodiment, the base payload springs 136 are part #RHL 200-400 from Moeller Manufacturing Company of Plymouth, Michigan.

Referring to Fig. 18, a preferred embodiment of the engine block assembly 120 is presented. In this embodiment, the engine block assembly 120 comprises four engine assemblies 140, two engine mounts 142, and a heat sink 144. Preferably, each of the motor assemblies 140 is connected to a power connector 146 (preferably three pin) and a feedback connector 148 (preferably seven pin). One end of the motor shaft 170 of each of the four motor assemblies 140 is preferably visible through two access holes 150 in each of the motor mounts 142. Two of the motor assemblies 140 face toward one of the motor mounts 142 and two of the motor assemblies 140 face toward the other of the motor mounts 142.

Referring to Fig. 19, a preferred embodiment of each of the motor assemblies 140 is presented. In this embodiment, each of the motor assemblies 140 preferably comprises a motor stator housing 160, a self-aligning bearing 162, two wave springs 164, a motor stator 166, a motor rotor 168, a motor shaft 170 , keys 172, a counterweight 174, a counterweight spacer 176, an angular contact ball bearing 178, a resolver rotor 180, a motor weight casing 182, a resolver stator 184, and a retaining ring 190. In a preferred embodiment, the resolver is Model No. JSSB-15-J-05K, Frameless Resolver, manufactured by Northrop Grumman, Poly-Scientific, Blacksburg, VA.

During operation, the motor assemblies 140 of the embodiment of Figs. 12-19 are activated by a controller (not shown) that causes two of the motor shafts 170 to rotate clockwise and two to rotate counterclockwise. As noted above, the motor shafts 107 are oriented parallel to each other and the pairs are operated in opposite directions of rotation with counterweight pairs 174 opposite each other on the horizontal axis and coincident on the vertical axis. As with the other embodiments, this arrangement produces substantially vertical linear forces with cancellation of horizontal forces.

Variation in the manner of mixing is achieved by using a motor controller or motion controller (not shown) to generate signals to control the frequency and amplitude of motor assemblies 140 to produce linear vibratory motion. In an alternative embodiment, the motor may be a servo motor, a stepper motor, a linear motor, or a direct current (DC) motor. By placing an accelerometer (not shown) on the payload assembly 74 and/or the motorblock assembly 120 to provide feedback control of the mixing motor, the agitation characteristics in the fluid or solid can be adjusted to optimize the degree of mixing and to produce a quality mix. In a preferred embodiment, the motor controller is Model No. 6K4, 6K 4-Axis Controller, manufactured by Parker Hannifin Corporation, Compumotor Division, Rohnert Park, CA. In a preferred embodiment, the accelerometer is a model No. 793 Accelerometer, manufactured by Wilcoxon Research, Gaithersburg, MD.

Control of a three-mass system includes two primary aspects. The first aspect includes control of the phase angle or the relative position of each of the servo motors with respect to each other. The sensors for this are the resolvers that are attached to the shaft of each motor. These devices send an absolute position signal to the motion controller which tracks position error from one motor to another. In turn, the motion controller then calculates and sends a correction signal back to the motors. This keeps the phase angles of the motors within a tolerance that is set in the control code.

The second aspect of the control system is the establishment and maintenance of a desired vibration amplitude. This is achieved by monitoring the amplitude of the movements of the payload mass (m1) with an accelerometer. Signals from the accelerometer are sent to the motion controller and compared to a value set by the operator. An error correction signal is then calculated and sent to the motors to increase or decrease their frequency and phase angle to achieve the desired amplitude.

The phase angle control of the motor control also has two aspects. The first aspect is to maintain position motor by motor and the second aspect is to control the magnitude of the power input to the system. Motor-to-motor position holding is necessary so that the resulting force input to the system is oriented in only one direction. This is achieved by controlling the position of the motor pairs. The motors are matched in pairs or sets so that each set has identical phase angles. The pairs of motors are then set in motion so that they have equal but opposite frequencies of rotation. Next, the phase position is controlled so as to add the forces resulting from the eccentric masses in a singular direction that is parallel to the orientation of the spring axes. The magnitude of the force is controlled by controlling the phase angle between pairs of motors. If the pairs of motors are 180 degrees out of phase with each other, the resulting net force is zero. When the phase angle between pairs of motors is zero degrees, the resulting net force is 100 percent of the sum of the four eccentric masses. The phase angles between these extremes result in forces that are lower than the maximum.

In summary, applicants have discovered systems and methods for applying acoustic energy to a reactor volume that can achieve a high level of mixing uniformity. The micromixing that is achieved and the effects in the combinations of frequency ranges, offset ranges, and acceleration ranges described herein produce very high quality mixers. The process described herein can be practiced with the preferred systems described herein and with single mass vibrators, dual mass vibrators, and piezoelectric and magnetostrictive transducers.

Liquid-to-liquid mixing is enhanced when a composition comprising a plurality of liquids is exposed to a vibratory environment that is preferably operative to vibrate the composition at a frequency between about 15 Hz and about 1,000 Hz with an amplitude between about 0.508 to about 12.7 mm (between about 0.02 inches and about 0.5 inches). Liquids that are not miscible are easily mixed when subjected to this condition. The normal boundary layers that prevent mixing break down and the liquids distribute freely and evenly over each other. In this vibratory environment, micromixing is achieved with the generation of 10 micron to 100 micron droplets. This vibratory process improves uniformity of droplet size and distribution, thus allowing greater mass transport, but the mixture separates easily when vibratory agitation is removed. The method adjustment between a preferred frequency between about 15 Hz and about 1,000 Hz with a preferred amplitude between about 0.508 and about 12.7 mm (between about 0.02 inches and about 0.5 inches) optimizes the transfer of acoustic energy to the fluid. This energy then generates a uniform distribution of droplets (larger than those generated with typical related procedures) that collide with each other to effect mass transfer from one droplet to another. After removal of acoustic energy, the liquids separate easily and quickly, thus effecting high mass transfer without creating an emulsion.

Mixing of a composition comprising a liquid, a gas, and a solid is enhanced when it occurs in a vibratory environment that is operative to vibrate the composition at a preferred frequency between about 15 Hz and about 1,000 Hz with a preferred amplitude between about 0.508 to about 12.7 mm (between about 0.02 inches and about 0.5 inches). Fluids (gas-liquid, gas-liquid-solid systems, and multiples of these systems) in the payload container are caused to develop a resonant/mixed state that establishes high levels of gas-liquid contact, an acoustic wave, and patterns. axial flow resulting in high levels of gas-liquid mass transport and mixing.

Typically, non-Newtonian or thixotropic (pseudo-plastic) fluids are difficult to mix. By placing a composition comprising these fluids in a vibratory environment that is operative to vibrate the composition at a preferred frequency between about 15 Hz and 1,000 Hz with a preferred amplitude between 0.508 and 12.7 mm (0.02 in. and 0.02 in.). .5 inch), fluidize and mix easily. Under these conditions, it is possible to mix said fluids containing one or more solids, one or more gases and one or more liquids.

Mixing of a composition comprising a liquid and a gas is enhanced when it occurs in a vibratory environment that is operative to vibrate the composition at a preferred frequency between about 15 Hz and 1,000 Hz with a preferred amplitude between about 0.508 and about 12 Hz. 0.7 mm (between about 0.02 inches and about 0.5 inches) to produce a gasified medium. Boundary layers are easily broken and gas is trapped in the fluid. Micrometer-sized bubbles are trapped in the liquid for long periods of time. This procedure is particularly effective for the gasification of liquids used to supply gases to bioreactors. Small bubbles subjected to acoustic energy produce "bubble pumping". This is the effect of compressing and expanding a bubble trapped in the fluid using acoustic energy. This instability causes the bubbles to be completely enveloped by the fluid under preferred operating conditions. The mass transfer from the gas trapped in the bubbles to the liquid is also affected by the increase in pressure on the bubble as the acoustic waves pass through the liquid. Henery's law states that the mass transfer from gas to liquid is proportional to the pressure of the gas in the bubble. This effect depends on the headspace or volume of gas relative to the volume of fluid in the mixing vessel. A relatively small volume of gas will produce very small bubbles with increased gas bubble pressure and bubble retention is achieved for longer periods of time after removal of acoustic agitation.

Mixing for the purpose of degassing a composition comprising a liquid and a gas (degassing) is enhanced when the composition is exposed to a vibratory environment that is operative to vibrate the composition at a preferred frequency lower than about 10 Hz to about 100 Hz and a preferred offset of less than about 0.635 mm (0.025 inches). Reducing displacement and frequency to these lower levels is particularly useful for expelling gas trapped in fluids. These conditions are effective for both thin liquids, such as water, and highly viscous, solid-laden liquids.

Physical reactions, such as heat transfer, mass transfer, and particle suspension, are greatly accelerated by exposing the reactants to a vibratory environment that is operative to vibrate the reactants at a preferred frequency between about 15 Hz and about 1,000 Hz. Hz with a preferred amplitude between about 0.508 and about 12.7 mm (between about 0.02 inches and about 0.5 inches). By placing media containing the reactants in such an environment, the physical forces that generate these reactions are actuated at higher rates. Similarly, the rate of chemical reactions increases due to improved contact and micromixing. Increasing the contact velocity of the media and the breaking or shrinking of boundary layers causes reactions to occur at higher rates.

The intrusion or infusion of liquids or liquid-entrapped gases into solid porous media is enhanced by placing the porous media in an operating environment to vibrate the porous media at a preferred frequency of from about 5 Hz to about 1,000 Hz with a preferred amplitude between about 0.508 to about 12.7 mm (between about 0.02 inches and about 0.5 inches). Boundary layers break down and fluids and gases are forced into, out of, and through the porous structure.

Low shear mixing applications are necessary to prevent damage to biological cultures to reduce damage to media. This is achieved by placing the cultures in a vibratory environment that is operative to vibrate the cultures at a preferred frequency of from about 5 Hz to about 1,000 Hz with a preferred amplitude between about 0.254 and about 5.08 mm (between about 0.01 inches and about 0.2 inches). Cell cultures are physically mixed with gases, solids, and liquids in an environment of low shear and minimal cell-to-cell collisions. Nutrients and waste products are transported to and from cell cultures with very low shear stress. This procedure also produces a more conducive cell culture morphology due to the low shear stress. Cells are prevented from agglomerating into large masses which block mass transfer to and from individual cells.

Incorporation of a solid into a liquid is enhanced by exposing the solid and liquid to a vibratory environment that is operative to vibrate the combination at a preferred frequency between about 15 Hz and about 1,000 Hz with a preferred amplitude between 0.508 and 12.7 mm (between 0.02 inches and 0.5 inches). Incorporation can be so complete that it approaches the theoretical maximum. By placing the fluid and solids in a vibrating environment, and as a result providing acoustic energy to the medium, the effect is to fluidize the mixture. In the process, micromixing is done throughout the vessel while macromixing the product. Complete and thorough mixing is achieved by using acoustic energy on solids loadings that were previously unachievable.

Similar to liquid mixing, solids are mixed by adding acoustic energy to achieve micromixing. A vibratory environment operating at a preferred frequency between about 15 Hz and about 1,000 Hz with a preferred amplitude between about 0.508 and about 12.7 mm (between about 0.02 inches and about 0.5 inches) provides the acoustic energy required to mix solids. The size of the solids can be from nanometer size to much larger particles. The acoustic energy supplied to the particles acts directly on the media to cause mixing. Other methods use components such as propellers to produce fluid movement through eddies that then mix the media. These eddies are dampened by the media and thus the mixing is localized close to the component that creates it. The acoustic energy supplied to the media is not subject to the location of the input because the entire volume of the mixing vessel is subjected to the energy at the same time.

Those skilled in the art will devise many variations of the invention. Some variations include embodiments where the oscillator mass is connected to the intermediate mass by springs and the intermediate mass is connected to the payload mass by springs. Other variations require embodiments in which the oscillator mass is connected to the payload mass by springs and the payload mass is connected to the intermediate mass by springs.

Although some embodiments are shown to include certain features, Applicants specifically contemplate that any feature described herein may be used in conjunction with, or in combination with, any other feature in any embodiment of the invention.

Claims (15)

1. Apparatus (10) to generate agitation comprising: a base (37); a first movable mass (12), wherein said first movable mass is movable in a first linear direction and in an opposite linear direction; a second movable mass (11), wherein said second movable mass is movable in the same directions as said first movable mass and is movably connected to said first movable mass by a first resilient means (25) and is movably connected movable to said base (37) by means of a second elastic means (27); a linear electromagnetic force transducer (38) rigidly connected to the first movable mass (12) and operative to produce a first vertical force on the first movable mass (12) in the first linear direction and a second vertical force on the first mass (12) moving in the opposite linear direction; Y a third movable mass (13), wherein said third movable mass (13) is movable in the same directions as said first movable mass (12) and is movably connected to said second movable mass (11) by a third means (26) elastic, in which the third mobile mass (13) is not directly connected to the first mobile mass (12). 2. Apparatus according to claim 1, further comprising: a mixing chamber (60) that is rigidly connected to said second mobile mass (11) or to said third mobile mass (13). 3. Apparatus according to claim 1 or claim 2, further comprising: electronic or electromechanical means for controlling the frequency at which said second mass (11) or said first mass (12) cyclically moves and/or the displacement of said first mass (12) as it cyclically moves. Apparatus according to any one of claims 1 to 3, wherein said elastic means (25, 26, 27) have elastic indices that are adjustable. 5. Apparatus according to any of the preceding claims, further comprising: electronic or electromechanical means to automatically adjust the characteristics of said elastic means (25, 26, 27), the magnitudes of the forces and the frequency at which the forces are applied, thus allowing control of the vibration frequency or the displacement of a payload to provide consistent and/or controlled operation of the apparatus in a variety of situations. Apparatus according to any of the preceding claims, in which the third mobile mass is connected to said base (37) by means of a fourth elastic means. 7. Apparatus according to claim 1, wherein: the linear electromagnetic force transducer (38) is rigidly connected to one side of the first moving mass (12), or the linear electromagnetic force transducer (38) is rigidly connected to the center of the first moving mass (12). 8. Apparatus according to claim 1, wherein: the first mobile mass (12) and the third mobile mass (13) are located at approximately the same elevation on the base (37); Y the first mobile mass (12) and the third mobile mass (13) are located on the second mobile mass (11). Apparatus according to claim 1, in which the second mass (11) comprises a plurality of additional masses, in which each of the additional masses is connected to the third mass (13) by means of an additional elastic means, and/ or in which the third mass (13) comprises a plurality of additional masses, in which each of the additional masses is connected to the second mass (11) by means of an additional elastic means. 10. Mixing procedure comprising: providing the apparatus (10) according to any preceding claim; Y causing the linear electromagnetic force transducer (38) to move the first moving mass (12) in the first linear direction and the opposite linear direction. A method according to claim 10, when dependent on claim 2, further comprising: placing a composition to be mixed in said mixing chamber (60). 12. Mixing method according to claim 11, wherein said composition comprises a first liquid or a gas entrapped in a second liquid and a porous solid medium having a boundary layer and wherein said mixing further comprises: exposing the porous solid media and the first liquid or gas entrapped in the second liquid to a vibratory environment operative to vibrate the composition at a frequency between 5 Hertz and 1,000 Hertz and at an amplitude between 0.51 mm (0 .02 inches) and 12.7 mm (0.5 inches); thereby breaking the boundary layer and forcing the first liquid or gas trapped in a second liquid to, from and through the porous solid media. The method of mixing according to claim 11, wherein said composition comprises a culture comprising a nutrient medium and a microorganism and wherein said mixing further comprises: exposing the culture to a vibratory environment operative to vibrate the composition at a frequency between 5 Hertz and 1,000 Hertz and at an amplitude between 0.25 mm (0.01 inches) and 5.1 mm (0.2 inches); thus achieving a low shear mixing of said composition. 14. Mixing method according to claim 11, wherein said composition comprises a solid and a liquid and wherein said mixing further comprises: exposing the solid and liquid to a vibratory environment operative to vibrate said composition at a frequency between 15 Hertz and 1,000 Hertz and at an amplitude between 0.51 mm (0.02 inches) and 12.7 mm (0 .5 inches), wherein said vibrating environment has a volume having parts; thereby subjecting all parts of the volume to a substantially equal amount of acoustic energy for substantially the same time and incorporating the solid into the liquid. 15. Mixing method according to claim 10, wherein the second moving mass (11) or the third moving mass (13) vibrates at a third harmonic frequency and is operative to produce a force cancellation effect, reducing or eliminating this way the forces transmitted to the surrounding environment. and increasing mixing efficiency.